Generator stream lining



W. H- KEIVIPTON, B. J. GUDGE, AND F. P. LAUFFER.

GENERATOR STREAM LINING.

APPLICATION FILED JULY 25.1918.

ELABSJFSQ. Pmmd (m. 31, 1922.

Patented @et. El, IQZZ.

WILLARD H. KEMPTON AND BENJAMIN 3'.

GUDGE, OF WILKINSBURG, AND FRANK P. LAUFJEER, OF IRWIN, PENNSYLVANIA,ASSIGNORS T0 WESTINGHOUSE ELECTRIC 2: MANUFACTURING COMPANY, ACORPORATION OF PENNSYLVANIA.

GENERATOR STREAM LINING.

Application filed July 25, 1918. Serial No. 246,768.

Vania, and FRANK P. LAUFFER, a citizen ofthe United States, and aresident of Irwin, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Generator StreamLinings, of which the following is a specification. Our inventionrelates to stream-lined cas- 1ng s and more particularly to stream-linedcaslngs or tail-pieces for the generators of aircraft wirelessinstallations, and it has for its object the provision of a laminated,mold-- ed body, of hollow stream-line design, which may be readilyapplied to, or removed from, the casing proper of the generator andwhich, as a rule, will partially enclose the generator casing.

' In this connection, a still further object which we have in view isthe provision of a stream-lined casing of the above described characterwhich shall be unusually light, although strong, and which will not beeffected by moisture, oils, or acids and one which is not inflammable. 5

A still further object which we have in mlnd is the provision of a novelmeans of uilding up the body of the casing, from sheets ofsuitably-impregnated fibrous material, in such manner that the built-upbody, consisting of a plurality of sheets or layers of such material insuperimposed relation, may be positioned in a mold and there be suitablytreated to harden the impregnating binder and to give proper shape andfinish to the resultant stream-lined casing.

We prefer, in practising our invention, to be able to employ fabricsheets, Woven in the usual manner, paper or sheets of cotton batting.For this reason, another object which we wish to accomplish is thedevelopment of a suitable pattern for. cutting the sheet material from aflat sheet in such manner that it ma be assembled smoothly and evenly inthe desired stream-line shape, either by assembling it about the coreofa mold or about a form of suitable character.

ennsylvania, BEN-- We have found, from practice, that the abovementioned object may be accomplished by cutting the several sheets,constltuting the body of the casing, in such manner that each sheetincludes one continuous marginal edge portion or band from one side ofwhich a plurality of tapering pointed streamers project, the bands inthe assembled article making up the larger open end of the casing andthe streamers being drawn together, edge to edge, to form the taperingend or point of the stream-lining.

Although various methods of holding the assembled streamers, of thesuccessive laminations' of. sheet material, may be devised and employed,we have found that a convenient method is to provide a relatively small,properly shaped wooden block to form a support for the smaller end orpoint of the casing in order that the several streamers may be tacked,or otherwise secured, to the block and be so held in place throughoutthe various steps of assemblage and during the positioning of theassembled body upon its core and within a suitable mold.

In the drawings, in which similar refer ence numerals indicatecorresponding parts throughout, Fig. 1 .is a side elevation of agenerator, such as is employed in aircraft wireless installations,showing our improved stream-lined casing or tail-piece applied; Fig. 2is a fragmentary plan of a sheet cut to proper shape for use in buildingthe easing; Fig. 3' is aside elevation of the finished casing; Fig. 4 isa fragmentary axial section showing the smaller end of the casing,together with the reinforcing Wooden block and theadjacent portion of aform used in assembling the casing; Fig. 5 is a corresponding viewshowing a modfied form of construction.

Primarily, our invention resides in the construction of a hollow casingor tail-piece for wireless generators by forming a properlystream-lined,'ho1low, laminated body of a suitable fibrous sheetmaterial impregnated with a binder. Various fibrous sheet mate rials maybe employed, such as a closely matted calendered material as paper, awoven fabric, such as duck, or a loosely matted spinnable fibrous sheetmaterial, such as cotton batting. If deemed advisable, various materialsmay be employed and, in any event, any one of a number of impregnatingmaterials may be used. Impregnating materials suitable for the purposeinclude Shellac, copal, casein, marine glue or a phenolic condensationproduct, such as bakelite. As

" a rule we prefer the use of bakelite because of the fact that alaminated body impregnated with bakelite may be rendered hard andimpervious to water, oils and acids by the application of heat andpressure and for the further reason that the mere molding of such abody,by the application of heat and pressure, provides an extremely smoothand highly polished surface which materially reduces air friction whenthe body is employed for stream-linings or like purposes.

In Fig. 1 we have conventionally illustrated a generator 1 having itsusual casing, the generator being located partly within our improvedstream-line casing or tailpiece 2 and partly in advanceof it, as shown.Preferably, that portion of the generator casing which is seated withinthe larger end of the tail-piece is reduced in diameter to receive suchlarger end in order that the exterior surfaces of the two may mergesmoothly into each other. Screws 3, rivets or other suitable means maybe employed for detachably or permanently securing the tail-piece inplace. The tail-piece is hollow in construction andmay preferably becircular in cross section, being open at its larger end and tapering toa point at its smaller end, the degree of this taper increasing inabruptness from somewhat to the rear of the larger end to the point ofthe casing, itself.

Although various means may be employed for fitting suitably impregnatedsheets of fibrous material to bring them to the desired shape and tostill keep the wall of the tail piece smooth and of uniform thicknem, weprefer to cut, or otherwise form, the sheets employed in the mannerillustrated in Fig. 2. To accomplish this, a form of the desired shapeand dimensions may first be made and the circumferences of this form, atspaced intervals from end to end, may be measured.

These circumferences may then be divided into an equal number of partsand the parts so obtained may be laid off upon a plain surface to plotthe curved lines 4 of Fig. 2. By this means, a pattern is provided-fromwhich sheets of suitably impregnated fibrous material 5 may. be out.Each of these sheets,.

as shown in Fig. 2, includes an uninterrupted marginal edge portion orband 6 and a plurality of streamers 7 projecting laterally from one sideof the band 6. These streamers t 7 taper from the band-portion 6 to theends' of the-streamers which terminate in points, \the side edges of thestreamers being slightly curvedfor a reason which will be laterapparent. The number of streamers, for any one pattern, is of coursedependent upon the dimensions of the stream-lined casing to be formedbut should preferably be as small band portions 6 of the various layersor I laminations of sheet material are drawn tightly about the largerend of a suitable form or core, and the streamers of the several bandsare laid against such form or core with their points brought together,at the point of the form, in such'a manner that the edges of eachstreamer engage smoothly against the edges of adjacent streamers, care 4being taken that the streamers of each successive layer shall breakjoints with the streamers of adjacent layers.

In order to facilitate this assembling of the several pre-shaped sheetsabout the form,

we may provide a small wooden block to which the points of the streamersmay be secured and which constitutes a permanent part of the finishedstructure, and construct the form upon which the body is built up, aswell as the core upon which it is molded, in a peculiar manner todetachably receive this block and hold it in place.

Such an arrangement is shown in Fig. 4 in which 8 represents the smallerend of a form,

this end being cut away at right angles to the axis of the form toprovide a plain surfacedface 9 having a central and preferablycylindrical projection 10. The wooden block 11 has a plain surfaced face12 for engagement against the face 9 ofthe form and a recess ,13 tosnugly receive the projection 10, so that, when the block is applied tothe form, it is detachably held in axial alinement with it. This blockcorresponds in shape to the shape of the smaller end or point of thestream-lined tail-piece, as indicated in Figs. 1 and 3, save that,at itspoint, it is formed with a shallow recess or depression 7 14 whichfacilitate centering of the article in a mold and which also rovides aneasy means by which a hole may be bored through the block after thecasing is finished the form 8, the first sheet of suitablyshapedmaterial is wrapped about the form and the ends of its streamersare brought into pos-ition against the block and secured in place bysmall tacks 15' or other suitable fastening means. Further layers ofsheet material are then successively applied until a body of the desiredthickness has been formed, the ends of the streamers of the severallayers being each secured to the block, the inner layers beingpreferably tacked to the larger or base portion of the block and theouter layers to the block at positions nearer its point. The free endsof the band portions 6 of the sev- 10 eral layers may be drawn tightlytogether about the larger end of the form and secured by cross-stitching16, as shown in Fig. 3,

but, as a rule, we have found that, if care is taken in assembling thelaminated body, there is no necessity for stitching the edges of anyband except that of the outermost layer together. Instead of usingseveral sheets a single sheet of suitable length may be wound spirallyabout the form.

After the body has thus been built up or assembled, it may be liftedfrom the form and placed upon a correspondingly-shaped core and then,together with its core, placed ,in a suitable mold and there .treated toharden and compact it. This treatment or curing may be done in variousways, depending upon the adhesive or impregnating material employed. Forinstance, if shellac has been employed asthe impregnating material, thebody, while in its mold, will be subjected to heat and pressure tosoften the shellac and to compress the several impregnated layers makingup the body after which the mold will be cooled while the body is stillheld under pressure, to harden the shellac.

On the other hand, if a phenolic condensation product is employed as abinder, the article willbe subjected to the combined action of heat andpressure while in its mold, the heat bein continued until such time asthe binder shall have reached its hard and substantially insoluble andinfusible state. This molding, if the mold surfaces be highly polishedor somewhat oiled, will insure not only a smooth but a highly polishedsurface upon the stream-lined tail-piece so that it will offer butlittle skin friction to the passage of air during its use.

In some instances, particularly upon small tail-pieces or casings of thecharacter illustrated, it may be difficult to assemble the ends of theStreamers accurately and to mold them carefully enough to obtain astrong and neat point.- Under these circumstances,

a slightly different method may be followed,

such as that illustrated in Fig. 5. As there shown, the wooden block 17,corresponding to the block 11, instead of being pointed is"substantially semispherical in outline and e the ends of the streamersare cut a little short and tacked on so' that their ends do not quitecome together at a point. With this arrangement, a suitable quantity ofany preferred molding composition 18 may be applied to the point of thebuilt-up body just previous to its being positioned in the mold. Suchmolding com osition may comprise any suitable inert 'ller, such asasbestos, wood-flour, ground duck or the like, impregnated with asuitable adhesive, as a binder, preferably the same adhesive as thatemployed in impregnating the sheet material. Obviously, under thesecircumstances, this added molding composition will be pressed into shapewhen the article is pressed and heated in the mold, and a strong andfinished point for the tail-piece will be provided, as a result.

Although we have illustrated and described a stream-lined tail piece forgenerators of aircraft wireless installations, together with a methodfor making it, it will be appreciated that, by practising our inven-.tion, possibly with minor changes, it will be possible to makestream-lined casings of various kinds and suited for various purposesand, furthermore, that the same construction may well be carried out informing the stream-lined front and endcaps of aircraft bodies.Furthermore, the stream-lined casing need not be of a laminated type.For

instance, it may be formed of papier mach, brought to the'proper shape,dried, treated with bakelite or another suitable binder and then moldedor otherwise cured.

We, therefore, reserve the right to make stream-lined structures forvarious purposes and to make such changes in the' methods employed asmay be best suited to the c1rcumstances, providing such changes comewithin the scope of the appended'claims.

WVe claim as our invention:

1. A stream-lined structure comprising a hollow body open at one end andclosed at the other end and tapering from its open to its closed end,the body being formed of superimposed layers of fibrous sheet materialim pregnated with a binder.

2. A stream-lined structure comprising a hollow body open at one end andclosed at the other end and tapering from its open to its closed end,the body being formed of superimposed layers of fibrous sheet materialimpregnated with a phenolic condensation product as a binder.

3. A stream-lined structure comprising a hollow body open at one end andclosed at the other end and tapering from its open to its closed end,the body being formed of superimposed layers of a cloth impregnated witha phenolic condensation product as a binder.

4. A stream-lined structure comprising a hollow body open at one end andclosed at the other end and tapering from its open to its closed end,the body being formed of superimposed layers of duck impregnated with aphenolic condensation product.

5. A stream-lined structure comprisin a hollow body open at one endandclose at the other and tapering from its open to its closed end, thebody being formed of fibrous sheet material impregnated with a binder,said sheet material being slitted.

6. A stream-lined structure comprising a hollow body open at one end andclosed at the other and tapering from its open to its closed end, thebody being formed of fibrous sheet material impregnated With a binder,said sheet material being out to provide a band and streamers.

7. A stream-lined structure comprising a hollow body open at one end andclosed at the other and tapering from its open to its closed end, thebody being formed of fibrous sheet material impregnated with a binder,

said sheet material being cut to provide a band and tapered streamers.

8. A'stream-lined structure comprising a hollow body open at one end andclosed at the other and tapering from its open to its closedlend, thebody being formed of fibrous sheet material impregnatedwith a

